Clean room structure



Dec. 5, 1967 RD. SCOTT 3,356,006

CLEAN ROOM STRUCTURE Filed Oct. 18, 1965 2 Sheets-Sheet 1 [VI/ENTOA?Raaeer D. Scar? Dec. 5, 1967 R. D. SCOTT CLEAN ROOM STRUCTURE 2Sheets-Sheet 2 Filed Oct. 18, 1965 e WWM. Nr. M 7W wfi m 0. R M

&/ 72- rap/vars United States Patent Ofifice 3,356,006 Patented Dec. 5,1967 3,356,006 CLEAN ROOM STRUCTURE Robert D. Scott, 1324 S. Glen Alan,West Covina, Calif. 91790 Filed Oct. 18, 1965, Ser. No. 497,290 18Claims. (Cl. 9833) ABSTRACT OF THE DISCLOSURE A clean room structure isprovided comprising walls including a ceiling and an underlying floorstructure an air passing sub-micron filter depending from the ceilingcentrally of the roomhaving a shell whose sides extend downwardly andconvergently from the ceiling, distributed apertures in the floorstructure including apertures directly below the filter, a blowercommunicating with the filter and operating to displace air into andthrough the filter so that the air is discharged from the filteroutwardly to the room sides and downwardly to the floor apertures in afan-shaped pattern transversely of the room and an air return ductsystem whereby the blower suction draws air downwardly through the floorapertures. The novel shape of air distribution in the clean roomstructure serves to carry contaminants from the working zone and doesnot induce potentially contaminated air from the room environment evenwhen the room is open-sided.

This invention has to do generally with so-called clean room or workingarea structures designed to provide and maintain for working personneland work being performed a clean atmosphere which results from thecombined effects of ventilating the work area with air cleansed bypassage through a sub-micron filtering medium, and so distributing thefiltered air that it sweeps the entire atmosphere of the area, and alsoif desired, working surfaces where dust or other contaminants may tendto tie osit. P Generally considered, the invention is predicated uponthe concept of providing a room structure, which may or may not itselfbe contained within a larger room or other enclosure, with a hollowsub-micron filtermounted centrally to the room ceiling to extendlongitudinally thereof, and so shaping the filter that the air dischargetherefrom completely sweeps the room atmosphere in a fan patternextending outwardly from the filter to the room sides and progressivelydownward throughout the full transverse extent of the floor. The roomsides may be open or closed, although for the majority of purposes thesides will be left open so that the room air going to the sides willexhaust into open atmosphere or a more confined atmosphere of a largerstructure. Provision is made for posi tively inducing the air flow anddistribution in the indicated pattern by providing an apertured floorstructure containing openings distributed laterally of the room, andparticularly directly below the filter, and utilizing a duct and blowersystem operating to draw the room air downwardly through the floorapertures, and if desired, to recircuate such air to the ceiling filter.As will appear, such return air may be vented in part and supplementedwith outside air, and provision may be made for temperature conditioningthe air going to the filter.

The invention further contemplates the provision of a longitudinallyextended table in direct underlying relation to the filter, the tabletop having distributed apertures in communication with the blowersuction so that air is caused to sweep and pass downwardly into andthrough a hollow interior of the table, thus to constantly clean itsworking surface by removal of dust or other particles.

These as well as various additional features and objects of theinvention will be more fully understood from the following detaileddescription of an illustrative em bodiment shown by the accompanyingdrawings in which:

FIG. 1 is a view showing the room structure in transverse cross section;

FIG. 2 is a longitudinal section taken on line 2-2 of FIG. 1, with anoptional additional feature;

FIG. 3 is a perspective showing of one of the filter segments;

FIG. 4 is an enlarged transverse section through the filter taken online 44 of FIG. 2;

FIG. 5 is a fragmentary enlargement of the filter structure; and

FIG. 6 is a fragmentary section taken on line 6 6 of FIG. 4.

Referring first to FIGS. 1 and 2, the room structure may becharacterized as comprising a ceiling 10, optionally of spaced sections11 and 12 sloping toward a central area 13, a floor structure 14composed preferably of a false floor 15 spaced above section 16 or abase surface 17, and end walls 18 and 19. The illustrated structure 10ordinarily will be accommodated within a larger room or other buildingarea to provide an isolated clean and dust free atmosphere as isrequired for various kinds of work that must be protected against dustor like exposure. Also most usually, though not necessarily in allcases, the sides of the room are left open at 20 to provide for sweepingexhaustion of air from the room interior to the outside atmosphere.

As best illustrated in FIG. 1, air is introduced downwardly andoutwardly into the room through a filter generally indicated at 21,which is suspended from the ceiling 13 to extend centrally andlongitudinally of the room as shown in FIG. 2. In the specificembodiment illustrated, the filter 21 is shown to have a transverseextent corresponding roughly to about one-third of the room width,although this relative filter dimension is variable as by reductionapproximating one-fourth the distance between the open sides of theroom. The invention broadly contemplates a transverse filterconfiguration according to which the sides of the filter convergedownwardly to a bottom extent centrally overlying the floor 14, and ifused, the

later described apertured table. Thus the general concept of the filtershape is that it be given a configuration such that air passing throughthe filter shell will sweep the room atmosphere in an essentially fanpattern extending, as indicated by the arrows, the vertical extent ofthe open sides 20 as well as the horizontal extent of the floor 14.

Preferably, though typically, the filter shell 22 is given an arcuatedownward curvature symmetrically in relation to the transverse extent ofthe room, and has an over-all segment cylindrical shape extendingbetween the end walls 18 and 19 of the room. While capable ofconstruction in any of various specific forms, the filter shell 22 willbe designed generally to contain a sub-micron filtering medium ormembrane which may be of any known suitable commercially availabletypes, as for example glass-asbestos membrane known as an AbsoluteFilter manufactured by Cambridge Filter Corporation of Syracuse, NY. Forpresent purposes it will suffice to characterize such known membranes ashaving intimately distributed pores capable of filtering from airpassing through the'pores, dust particles as small as submicron in size,thus to thoroughly cleanse the air to substantially com- O pleteelimination of dust particles that could possibly contaminate, in thisinstance, the clean room atmosphere.

FIGS, 3 to 6 show an illustrative construction of the filter shell 22according to which the latter is made in sections each comprisingarcuate ends 23 having bolt holes 24 and pieces 25 attachable bysuitable means such as bolts or screws or other mountings to the centralceiling 12. Air seals between each engaging pair of ends 23 may beprovided by an arcuate tongue 231 received within a corresponding groove232, as shown in FIG. 6. Suecessive sections of the filter shell arefastened together by bolts 26 inserted through the holes 24. Each of thesections contains radially extending supports 27 projecting in staggeredor offset relation from inner and outer screen enclosures 28 and 29,these supports typically being made of cellular paperboard havingsufficient strength and rigidity to support and position the filtermembrane 30. The latter being thin, flexible and of sub-micron porosityas previously indicated, is suitably secured at its sides to the sectionends 23 and is extended reversely in essentially pleated or accordionshape between the supports 27, thus to provide adequately large surfacearea for the membrane to pass the necessary air throughput withoutexcessive pressure drop.

At suitable intervals the filter segments may contain light fixtureinserts 31 for illumination of working area directly below. The ceilingstructure may contain additional light fixtures as at 3-2.

Provision is made in the floor structure 14 for inducing air flow fromthe room atmosphereat locations so distributed as to assure maintenanceof the illustrated flow pattern. Such induced air flow may be effectedcontinuously across the floor or at such selected locations as will inpractical effect maintain the fan-shaped air flow pattern toward andacross the bottom of the room. As illustrative, grills 33 may beprovided in the false floor for induction of air into the sub-floorspace 34, and similar grills 35 and 36 may be utilized for thewithdrawal of air from the central floor area. The space 34 provides aduct leading openly into compartment 37 beyond the room end Wall 19, anditself having an end wall 38. The compartment contains a motor drivenblower 39, the suction of which induces air flow from the roomatmosphere down through the false floor apertures or grills, at least aportion of such air being recirculated by the blower upwardly throughcompartment 37 into duct 40' within the filter shell, thence to beforced out through the filter in the described pattern. Provision may bemade for admitting outside air to the compartment 37 as through grills41 and 42- or other appropriate means. Additionally, it may be desiredto temperature condition the air going to the filter, for which purposesa combined and selectively operable heating and cooling unitdiagrammatically indicated at 43, may be installed in the compartment.

If for any reason it is desired to alternate or supplement the airdelivery of blower 39, air from the outside through e.g. an openablevent V, may be provided by one or more ceiling-supported blowers 44positioned within a suitable housing 45 and discharging downwardly intothe filter duct 40. This same structure may be used instead of thedescribed system employing blower 39 for air delivery to the filtershell, with or without induced air recirculation. Thus, by providingsuitable ducting as at 451 communicable with space 34 as by way of aduct or chamber 37, and by providing an air control such as valve ordamper 452 which may be closed as in FIG. 2, or swung open to the 452adotted open position, the blowers 44 may operate to dischargenon-recirculated air when the valve is closed, or to induce anddischarge recirculated air. Under the latter condition, closure C may beraised to the dotted C position to close oft direct communicationbetween chamber 37 and the filter shell.

-A constantly cleansed, extended working surface may be provided bytable generally indicated at 46 which may be extended the full length ofthe room, or any portion thereof, the table being shown to have a hollowbase 47 in open communication wtih the floor apertures 36, and a top 48containing apertures 49 so that air passing downwardly from the filtercan be induced by the blower suction down through the table to therecirculation duct 34. The table top apertures 49 are given sufficientlyclose spacing and distribution over the working surface of the table, asto assure constant and substantially'complete.

removal in the induced air streams, of dust and othersolid particleswhich might otherwise be retained upon the table top.

It is to be understood that the drawings are illustrative of theinvention in typical embodiments and that various changes andmodifications may be made without departure from the invention in itsintended scope.

I claim:

1. A clean room structure adapted to accommodate working personnelcomprising,

(A) walls including a ceiling and an underlying floor structure,

(B) a hollow elongated air passing sub-micron filter depending from theceiling centrally within the room and having a filter supporting shellthe sides of which extend downwardly and convergently from the ceiling,

(C) distributed apertures in said floor structure including aperturesdirectly below the filter,

(D) a blower communicating with the filter and operating to displace airinto and through the filter so that the air is discharged therefromoutwardly to the room sides from near the ceiling and downwardly to saidfloor apertures in a fan-shaped pattern extending radially from saidfilter within and transversely of the room thereby to positivelydisplace and sweep the room atmosphere both outwardly and downwardly insaid pattern, and

(B) an air return duct system whereby the blower suction drawings airdownwardly through the floor apertures.

2. The structure of claim 1, in which the room sides are open.

3. The structure of claim 1, in which the shell of said filter is arcuaely curved.

4. The structure of claim 3, in which the room sides are open and saidfloor apertures are located both beneath and laterally offset from belowthe filter.

5. The structure of claim 1, in which said floor structure includes anupper false floor and said duct system includes space below the falsefloor.

6. The structure of claim 1, including also a table directly underlyingsaid filter and having an apertured top through which air is drawndownwardly to and through said floor apertures directly below thefilter.

7. The structure of claim 6, including a light fixture carried by thebottom of the filter shell to centrally illuminate the table.

8. The structure of claim 6, in which the filter shell is ofsubstantially segmental cylindrical form.

9. The structure of claim 6, in which the sides thereof are open so thatair from the filter sweeps the room atmosphere outwardly from the roomas well as downwardly through the table top and floor structure.

10. The structure of claim 6, in which said floor structure includes anexposed false floor having an air space therebeneath and communicatingwith the blower, and said table has a hollow base through which thetable top apertures communicate with said air space.

11. The structure of claim 10, including also walls at one end of theroom forming an air duct containing the blower and interconnecting saidspace with the filter.

12. The structure of claim 10, including means in said gilct fortemperature conditioning the air going to the ter.

13. The structure of claim 10, including means for admitting atmosphericair to said duct.

14. The structure of claim 1, in which said filter comprises pleatedmicro-porous sheet material and means for supporting the material in itspleated form.

15. The structure of claim 6, in which said filter comprises pleatedmicro-porous sheet material and means for supporting the material in itspleated form. 16. A clean room structure adapted to accommodate workingpersonnel comprising,

(A) walls including a ceiling and an underlying floor,

(B) a hollow elongated filter shell depending from the ceiling centrallyof the room and having an air passing shell the sides of which extenddownward- =ly and convergently from the ceiling,

(C) a sub-micron filter membrane within the shell and serving to passand filter air from within the shell into the room, and

(D) blower means communicating with the filter shell and operating todisplace air into the filter and through the membrane so that the air isdischarged downwardly and outwardly in a fan-shaped patternsymmetrically transversely of the room extending from the ceiling oneither side of said filter membrane to the sides thereof to and acrossthe floor.

References Cited UNITED STATES PATENTS 3,084,609 4/ 1963 Onstad.3,115,819 12/1963 Mahlmeister 98----33 3,158,457 11/1964 Whitfield 9833MEYER PERLIN, Primary Examiner.

1. A CLEAN ROOM STRUCTURE ADAPTED TO ACCOMMODATE WORKING PERSONNELCOMPRISING, (A) WALLS INCLUDING A CEILING AND AN UNDERLYING FLOORSTRUCTURE, (B) A HOLLOW ELONGATED AIR PASSING SUB-MICRON FILTERDEPENDING FROM THE CEILING CENTRALLY WITHIN THE ROOM AND HAVING A FILTERSUPPORTING SHELL THE SIDES OF WHICH EXTEND DOWNWARDLY AND CONVERGENTLYFROM THE CEILING, (C) DISTRIBUTED APERTURES IN SAID FLOOR STRUCTUREINCLUDING APERTURES DIRECTLY BELOW THE FILTER, (D) A BLOWERCOMMUNICATING WITH THE FILTER AND OPERATING TO DISPLACE AIR INTO ANDTHROUGH THE FILTER SO THAT THE AIR IS DISCHARGED THEREFROM OUTWARDLY TO